The Preparation of 21,21‐Dimethylprogesterone.

Abstract

Steroids Steroids U 0300The Preparation of 21,21-Dimethylprogesterone. -A facile synthesis of the title compound (V) involving kinetically controlled alkylation of pregnenolone acetate (I) as the key step is given. (Yields in g). -(HANSON*, J. R.; KIRAN, I.; SCARBROUGH, C.; J. Chem. Res., Synop. 2003, 5, 301-302; Sch. Chem., Phys. Environ. Sci., Univ. Sussex, Brighton BN1 9QJ, UK; Eng.) -F. Santoso 03-188

The Conformation of the Side Chain of 21-Alkylpregnanes

“…The preparation of compound 2 has been described previously. 8 Methylation of 16α,17α-epoxypregnenolone: 16α,17α-Epoxypregnenolone (1.5g) in tetrahydrofuran (60 cm 3 ) was added to a suspension of sodium hydride (1g, 60% in mineral oil) in tetrahydrofuran (15 cm 3 ) and treated with methyl iodide (10 cm 3 ) at 0°for 14 h. The solution was then acidifed with dil. hydrochloric acid, concentrated in vacuo and the residue taken up in ether (300 cm 3 ).…”

“…The substrates were prepared by the methylation of pregnenolone (1) and 16α,17αepoxypregnenolone with excess sodium hydride and methyl iodide. 8 This gave 21,21-dimethyl-3β-methoxypregn-5-en-20one (2), 21,21-dimethyl-16α,17-epoxy-3β-methoxypregn-5-en-20-one (3) and its 21,21,21-trimethyl analogue (4). The 21,21-dimethyl and 21,21,21-trimethyl-16α,17-epoxides were separated by chromatography.…”